Systems and methods for removal of urine

ABSTRACT

An arrangement adapted for enhanced continuous flow of urine in a catheterized patient, the arrangement comprising a catheter tube having an inner diameter of less than six millimeters, said tube having an inner surface which is hydrophobic at least along a first segment thereof and being adapted to provide a continuously negative fluid pressure therein.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Ser. No. 14/037,371filed on Sep. 26, 2013, which is a continuation of U.S. Ser. No.12/669,494 filed on Jul. 5, 2010, now U.S. Pat. No. 8,568,387, which isa national phase of International Application No. PCT/IL2008/000986filed on Jul. 16, 2008, which claims priority to Israeli PatentApplication No. 184632 filed Jul. 16, 2007 and Israeli PatentApplication No. 192774 filed Jul. 13, 2008 the entirety of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods forremoval of urine from a patient and more specifically to improvedhygienic systems and methods for removal of urine from a catheterizedpatient.

BACKGROUND OF THE INVENTION

There are many situations in which a person, such as a hospitalizedpatient is unable to excrete waste products in a bathroom. Unconsciouspatients, paraplegics, some post-operative patients and incontinentpatients all require means to continuously or semi-continuously removeurine without leakage thereof and risk of urinary tract infections(UTIs).

Many different types of urinary catheters have been devised toeffectively remove urine from patients. For example:

GB1426429A, assigned to Simpla Plastics, describes a urinary collectionapparatus comprising a collection bag and a tube connected at one end tothe bag and having a connector cap for connection to a catheter at itsother end, the tube comprising at least a portion which is of a materialwhich is self-sealing when punctured by an instrument e.g. a hypodermicsyringe, for withdrawing a sample of urine. The portion may comprise asleeve of butadiene concentric with, and closely gripping the tube. Theportion may form an integral part of the tube or the whole tube may becovered by a butadiene or an other self-sealing sleeve. The bag isprovided with a drainage valve as disclosed in GB1310581 and has aone-way inlet valve. A graduated scale is provided on one face of thebag.

U.S. Pat. No. 3,861,396A to Bruckner describes means for eliminating anegative pressure problem, e.g. in a closed urinary system comprising acatheter, a downwardly extending tube and a collection bag. The tube hasan internal coating of a hydrophilic polymer, preferably a2-hydroxyethyl methacrylate polymer, or can be made completely of thehydrophilic polymer.

Bruckner describes there being a major problem with these systems, whichis the build-up of negative pressures in the bladder for example, due tothe build-up of the fluids columns in the various cannulae (lumens),e.g. see Vaillancourt U.S. Pat. No. 3,583,401.

This build-up is due to a combination of: a) closed system—whichprecludes the influence of atmospheric pressures which would break thiscolumn, and b) the surface tension of the tubing which acts to hold orretain the fluid in the tube.

Methods currently used to overcome this problem include: large boredrain tubing and the placing of a vent in the catheter connector. Theformer solution suffers from the limitation that the product is bulkyand difficult to work with, whereas the latter has been demonstrated toonly work for a very short period of time before the filter element getsclogged due to infestations, and/or hydrostatic pressures. Thedisclosure of '396 is concerned with a novel method which allows for theuse of smaller bore tubing, as well as functioning over the life of thedrainage system.

Briefly, '396 is concerned with using a hydrophilic tubing having aninternal diameter of at least 0.2 inch to prevent capillary action asthe connecting member (drainage tube) between the cannulae andcollector. It has been found that a hydrophilic tube (havingwater-wetting properties) will not support a column of fluid even thougha vacuum may be applied at one end.

U.S. Pat. No. 3,902,492, to Greenhalgh, describes a catheter for thecontinuous irrigation of the bladder which has a drainage tube for theremoval of fluid from the bladder, an auxiliary axial bore extendingthrough the wall of the drainage tube, and an irrigation tube extendingfrom the axial bore beyond the tip of the catheter. The irrigation tubehas a plurality of radial discharge outlets. During use, the irrigationtube curves around the bladder; fluid passes through the irrigation tubeto provide a discharge spray and a turbulent flow of liquid in thebladder. This provides for a peripheral bladder irrigation which is animprovement over a single discharge point near the entry of a catheterinto a bladder. The catheter also preferably has a second axial bore inits wall which terminates in an opening beneath a sheath of expandablematerial which can be inflated by fluid applied under pressure throughthe second axial bore, to secure the catheter in place.

U.S. Pat. No. 6,045,542, to Cawood et al., describes a urine collectionbag having the basic features appearing in U.S. Pat. No. 4,449,971. Thebag also includes an improvement in the form of an extendable drain tubethat is normally retracted and retained in flat coiled condition againstthe front wall of the bag. The tube is biased into its coiled conditionby the elastic memory of the thermoplastic material from which it isformed and, in a preferred embodiment, the flat coil is oval-shaped withits major axis extending generally vertically when the bag is worn. Aretention strap attached to the front wall of the bag serves to hold thedrain tube in its coiled condition against the bag's front wall. A valveis located at a distal end of the drain tube, which is used to controldrainage. The location of the valve prevents spillage of residual urineupon recoil of the drain tube.

U.S. Pat. No. 7,094,220 to Tanghoj et al, describes a catheter assemblyallowing for non-contaminated insertion of a catheter into a urinarycanal. The assembly includes a package for the catheter and anapplicator to be used for guiding the catheter into the urinary canalwithout touching the catheter by holding the catheter via walls of theapplicator. The assembly further comprises clamping means for pressingthe walls of the applicator into engagement with the catheter. Thepresent invention further relates to an applicator with integratedclamping means to be used with the assembly.

The catheter or at least a section thereof may be provided with ahydrophilic surface. When treated with a liquid swelling medium, such asurface will provide an excellent lubrication for the insertion and alsoprovide compatibility with the body tissue.

US2006189962A to Burtoft, describes a urinary drainage bag for drainingurine from the navel as a result of a urinary diversion. The meansinclude a urine collection bag, a reflux chamber attached to thecollection bag for accommodating urine backflow and working out bubbles,a multi-size catheter tip extending upwardly from the reflux chamber forattachment to a transfer or catheter tube, a urine discharge openingadjacent the lower end of the collection bag for draining urine from thecollection bag, and a fluid measurement scale imprinted on the front ofthe collection bag for measuring the amount of urine held within theurine collection bag.

The urinary drainage bag also includes a tether adjacent the upper endof the collection bag for conveniently hanging the collection bag, and ahandle and mounting hook are also attached to the upper end of thecollection bag for supporting the urinary drainage bag on a bed railing.

Thus, as will be noted from the publications hereinabove, the currentstate of the art is to use a catheter having at least part of the tubingthereof comprising a hydrophilic surface. Additionally, some of thesepublications relate to the negative pressure in the bladder, due to thebuild-up of the fluids columns in the various cannulae (lumens) as beinga problem, which U.S. Pat. No. 3,861,396 sought to overcome.

It is to be noted, and as will be discussed hereinafter with regard tocomparative FIGS. 1 and 2 relating to prior art arrangements, that thereare still several major problems with the prior art arrangements whichresult in infection in catheterized patients both during catheterizationand during the changing of the catheter arrangement.

Thus there is still a need to provide inexpensive, versatile urinarycatheters, which allow for use over long periods of time with reducedrisk of UTI.

Therefore, it is an object of some aspects of the present invention toprovide hygienic systems and methods for collecting urine from apatient.

In preferred embodiments of the present invention, improved methods andnovel apparatus are provided for collection of urine whereby thecollection unit remains sterile throughout the collection time.

In other preferred embodiments of the present invention, a method andsystem are described for removing urine, under a constantly negativepressure, from a patient.

SUMMARY OF THE INVENTION

More particularly, the present invention provides an arrangement adaptedfor enhanced continuous flow of urine in a catheterized patient, thearrangement comprising a catheter tube having an inner diameter of lessthan six millimeters, said tube having an inner surface which ishydrophobic at least along a first segment thereof and adapted toprovide a continuously negative fluid pressure therein

In especially preferred embodiments of the present invention said tubeis adapted to provide a continuously negative fluid pressure of lessthan 50 cm water or the equivalent thereof.

By the term “or the equivalent thereof” it is intended to denote thatthere are many ways of measuring pressure and that the following areconsidered to be substantially equivalent.

-   -   50 cm of water    -   0.05 Bar    -   50 Milli Bar    -   0.049 Atmosphere    -   3.75 cm Mercury    -   1.476 Inches Mercury    -   0.05 Kilogram/cm squared    -   5 Kilopascal    -   0.725 PSI.

As stated, said tube has an inner surface which is hydrophobic at leastalong a first segment thereof, and in preferred embodiments of thepresent invention said tube is disposed to provide a down-corner portionproximal to a first end thereof and a riser portion proximal to a secondend thereof and said tube has an inner surface which is hydrophobic atleast along said down-corner portion thereof.

In especially preferred embodiments of the present invention, the innersurface of said tube is hydrophobic along its entire length.

Thus said tube can be constructed of a hydrophobic material or the innersurface thereof can be coated with a hydrophobic material.

In preferred embodiments of the present invention, said tube is adaptedfor fluid conveying attachment to a catheter and for attachment to aurine collection bag.

In some preferred embodiments of the present invention said tube isadapted for one time, one-way, non-releasable attachment to a catheter.

In other preferred embodiments of the present invention said tube isadapted for non-releasable attachment to a urine collection bag.

In some preferred embodiments of the present said tube is non-releasablyattached to a urine collection bag.

In other preferred embodiments of the present invention said tube isnon-releasably attached to a catheter.

Also provided according to the present invention is a method forenhanced continuous flow of urine in a catheterized patient comprising:

a. providing an arrangement comprising a hydrophobic catheter tubehaving an inner diameter of less than six millimeters, said tube havingan inner surface which is hydrophobic at least along a first segmentthereof and being arranged to provide a continuously negative fluidpressure therein; and

b. non-releasably attaching said hydrophobic catheter tube to saidurinary catheter unit, and releasably attaching said tube to a urinecollection bag, said catheter unit being adapted to continuously removefluid from the patient and to convey said fluid into said tube under acontinuously negative fluid pressure.

The invention also provides, a system for enhanced continuous flow ofurine in a catheterized patient comprising:

a. a catheter tube having an inner diameter of less than sixmillimeters, said tube having an inner surface which is hydrophobic atleast along a first segment thereof and being adapted to provide acontinuously negative fluid pressure therein;

b. a urinary catheter unit, said catheter unit being adapted to conveysaid fluid through said tube; and

c. a urine collection apparatus releasably and fluidly connected to saidtube.

In preferred embodiments of said aspect of the invention, said tube isprovided with a first connector for attachment to a catheter and at asecond connector for attachment to a urine collection bag.

In preferred embodiments of the present invention said tube has an innerdiameter of less than five millimeters.

In especially preferred embodiments of the present said tube has aninner diameter of less than four millimeters.

Preferably said tube is adapted for non-releasable attachment to acatheter.

In some preferred embodiments of the present invention said tube isnon-releasably attached to a catheter.

Preferably, said tube comprises at least one hydrophobic materialselected from a thermoplastic elastomeric material, a thermoplasticmaterial, a curable elastomeric material, a polyimide resin; anelastomer and mixtures or blends thereof.

In said preferred embodiments, said material is preferably selected fromat least one of polypropylene (PP), polyvinyl chloride (PVC),polyurethane (PU), polyethylene (PE), EVA, latex, and Kraton™ andmixtures or blends thereof.

In some preferred embodiments of the present invention said tube isconnected to a urinary catheter unit, said catheter unit beingconstructed and adapted to remove fluid from the patient and to conveysaid fluid into said tube.

In preferred embodiments of the arrangement of the present inventionsaid tube is disposed to provide a down-corner portion proximal to afirst end of said tube and a riser portion proximal to a second end ofsaid tube.

Preferably, said tube is configured and adapted to provide a continuoushead of fluid from the patient to the down-corner portion of the tube.

In especially preferred embodiments of the present invention said tubeis configured and adapted to remain full of urine during operation.

As stated hereinbefore, in preferred embodiments the arrangement is suchthat a negative height difference between said second end and saidpatient is arranged to provide said continuously negative fluid pressureof between 5-50 cm water or the equivalent thereof.

As will be discussed hereinafter, in especially preferred embodiments ofthe present invention, said tube is adapted to maintain a meniscus headof fluid along at least a portion of said tube without interruption andin the most preferred embodiments said tube is adapted to becontinuously sterile over a period of time as a result of a meniscushead of fluid moving from said patient to said urine collection bagalong said tube without interruption.

In especially preferred embodiments of the present invention theapparatus and arrangement of the present invention is adapted to preventurinary tract infections in the patient as a result of the continuousnegative fluid pressure in the tube and the other features described andclaimed herein.

Furthermore, said arrangement is adapted to continuously remove liquidfrom said patient so as to substantially prevent the accumulation of abolus in the bladder of the patient.

As will be realized, in its preferred embodiments, said arrangement isconstructed and operative to provide a continuously negative pressure inthe tube and to the bladder of the patient.

A further aspect of the present invention relates to the use of ahydrophobic catheter tube having an inner diameter of less than sixmillimeters in the construction of an arrangement for enhancedcontinuous flow of urine in a catheterized patient, wherein said tubehas an inner surface which is hydrophobic at least along a first segmentthereof and being arranged to provide a continuously negative fluidpressure therein.

In another aspect of the present invention, there is provided acatheterization kit comprising a hydrophobic catheterization tube havingan inner diameter of less than 6 mm and provided with a first connectorfor non-releasable attachment to a catheter and with a second connectorfor releasable attachment to a urine collection bag and a catheter.

In preferred embodiments of the present invention said catheter tubewill preferably have a bore to wall thickness ratio of about 3:1.

In some preferred embodiments of the present invention the tube will beprovided with graduated markings along its length such that each markingwill corresponding to a specific volume thereby providing the abilityfor manual readings in the initial stages of flow, especially when theflow is very low and before the tube is full.

In some preferred embodiments of the present invention there will beprovided a non-return valve on the collection bag where the urine enterssaid bag, so that there will be no back-flow of contaminated urine intothe tube from the collection bag and so that when the pipe isdisconnected there will be no spillage of urine from the collection bag.

In other preferred embodiments of the present invention there will beprovided an air valve in the tube in the region where connection is madeto the collection bag, thereby preventing the creation of a vacuum whenurine samples are taken at a sample port situated in the region of thecatheter connection.

In especially preferred embodiments of the present invention theinternal surface of the tube is highly polished in order to enhance themaintenance of the meniscus.

While the invention will now be described in connection with certainpreferred embodiments in the following examples and with reference tothe attached figures so that aspects thereof may be more fullyunderstood and appreciated, it is not intended to limit the invention tothese particular embodiments. On the contrary, it is intended to coverall alternatives, modifications and equivalents as may be includedwithin the scope of the invention as defined by the appended claims.Thus, the following examples which include preferred embodiments willserve to illustrate the practice of this invention, it being understoodthat the particulars shown are by way of example and for purposes ofillustrative discussion of preferred embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description offormulation procedures as well as of the principles and conceptualaspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood from the followingdetailed description of the preferred embodiments thereof, takentogether with the drawings, in which:

FIG. 1a is a simplified pictorial illustration showing a prior arthydrophilic urinary catheter system for collecting urine from acatheterized patient;

FIG. 1b is a simplified pictorial illustration showing a prior arthydrophilic urinary catheter system for collecting urine from acatheterized patient;

FIG. 1c is a detailed view of part of the arrangement seen in FIG. 1B.

FIG. 2 is a simplified pictorial illustration showing a urinary catheterarrangement, in accordance with an embodiment of the present invention;

FIG. 2a is an enlarged cross-section of the tube of the presentinvention; and

FIG. 3 is a perspective view of a catheterization kit comprising acatheterization tube provided with means for attachment to a catheterand for attachment to a urine collection bag and a catheter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In order to illustrate the specific advantages of the present invention,a few of the problems associated with prior art urinary catheter systemsare now described.

Reference is made to FIG. 1a , which is a simplified pictorialillustration showing a hydrophilic prior art urinary catheter system forcollecting urine from a catheterized patient.

System 100 comprises a urinary catheter unit 102 connected to a tube104. The tube is typically of a hydrophilic material, as exemplified inU.S. Pat. No. 3,861,396A. The downwardly extending tube normally hangsover the edge of a bed and is fluidly connected to a collection bag 106.The collection bag is typically located on the floor or closely hangingthereabove. The hydrophilic surface of tube 104 normally allows urine totrickle down a surface thereof without building up a negative pressure.

Reference is now made to FIGS. 1b and 1c , which is a simplifiedpictorial illustration showing a prior art hydrophilic urinary cathetersystem 150 for collecting urine from a catheterized patient. System 150comprises a urinary catheter 176 connected to a tube 154. The downwardlyextending tube normally hangs over the edge of a bed and is fluidlyconnected to a collection bag 156. The collection bag 156 is typicallylocated on the floor or closely hanging thereabove.

The prior art tubes typically are of a diameter greater than 6 mm and assuch urine drops simply fall through the tube until reaching the loop158 thereof.

In such an arrangement, urine 164 typically accumulates in a loop 158 ofthe tube connecting between a down-coming portion 160 thereof, having avertical height hd (the difference in height from the bladder of thepatient to the lowest point 170 of down-coming portion 160) and a riserportion 162 thereof. The riser portion has a vertical height, hr,measured from lowest point 170 to highest point 172.

As urine 164 accumulates in loop 158, the riser portion and down-cornerportion of tube 154 gradually collect urine therein. Normally, at apseudo-steady state there is a constant “U-shaped” accumulation of urine164 in the tube and an air trap 166 above the urine in the risersection. This air trap 166 may contain contaminated air and lead to theaccumulation of bacterial or other colonies 168 on the inner surface ofthe tube. These colonies or bacteria/other microbes therefrom may thenbe drawn into the bladder under various circumstances as the height ofthe accumulation of urine 164 in the tube increases due to the positivepressure in the tube between the bladder 152 and the beginning of loop158 and induces a urinary tract infection (UTI).

In many medical centers, the “U-shaped” urine accumulation is milked outof the tube 154 and air enters from the collection apparatus 156 intothe tube 154. Again, this air may contain microbial or othercontaminants and may induce UTI in the patient.

It is to be understood that the collection bag is usually provided witha tap 174 from which urine 164 is emptied at least once a day. Uponemptying of the urine 164, air from the surroundings is sucked into andenters the collection bag 156, and since air normally contains bacteriaand since the bag is a warm, humid environment, bacteria naturallybreeds within the bag, which bag is not changed within a period ofbetween 2 weeks and a month.

When the “u-shaped” urine accumulation is milked out of the tube 154,the bolus of urine which is normally formed in the bladder, flowsthrough the tube, and creates a suction from the bladder to the tube tothe urine collection bag, and so the infected air from the urinecollection bag is often sucked into the bladder causing infection.

Turning now to FIGS. 2 and 2 a, there is seen a simplified pictorialillustration showing a urinary catheter arrangement 200, in accordancewith an embodiment of the present invention.

The arrangement of the present invention is arranged for enhancedcontinuous flow of urine in a catheterized patient and for preventingurinary tract infections in the patient, the arrangement comprises ahydrophobic catheter tube 204 having a diameter of less than sixmillimeters, the tube being arranged to provide a continuously negativefluid pressure of less than 50 cm equivalent of water therein as aresult of a meniscus 276 forming at the beginning of a flow of urine 164from the bladder 202 of the patient as a result of the narrowness of thetube and the repulsion of the urine from the hydrophobic surfaces of thetube, whereby during operation, the tube is always full of urine.

As a result, a natural negative pressure builds up in the tube whichserves to continuously suction urine from the bladder 202 in a closedsystem, keeping the bladder empty resulting in a steady flow which doesnot allow for air spaces and bacterial build-up in the tube in the areaadjacent the bladder.

The difference in the length of the down-coming portion 264 to the riserportion 266 is normally less than 60 cm, preferably less than 50 cm.This difference in height below the level of the bladder 202 of thepatient and the collection bag 214, is adapted to induce a negativepressure in the bladder of the patient, as will be explained in moredetail hereinbelow.

Typically, tube 204 has a diameter of less than five millimeters.Preferably, the diameter is less than four millimeters.

Tube 204 comprises at least one hydrophobic material preferably selectedfrom a thermoplastic elatomeric material, a thermoplastic material, acurable elastomeric material, a polyamide resin; an elastomer andmixtures or blends thereof.

The tube may be made of the hydrophobic material or internally linedwith the hydrophobic material as is known in the art. The material maybe selected from, but is not limited to, at least one of polypropylene(PP), polyvinyl chloride (PVC), polyurethane (PU), polyethylene (PE),EVA, latex, and Kraton™ and mixtures or blends thereof.

Arrangement 200 is constructed and operative to remove urine from abladder 202 of a patient 208, with the tube being preferablynon-releasably connected at a first end 210 to a urinary catheter 203,and the catheter 203 being constructed and operative to remove fluidfrom the bladder of the patient and to convey urine into tube 204.

The arrangement of the present invention comprises tube 204 beingreleasably and fluidly connected at a second end 212 to a urinecollection apparatus 214.

Tube 204 is further provided with clamp means 205 which are used toclose the tube 204 when the urine collection apparatus 214, e.g., aurine collection bag, is to be replaced.

As will be realized, by using clamp means 205, the negative pressure intube 204 is retained and thus the urine collection bag can be replacedat shorter intervals than that of the replacement of the tube 204 andthe attached catheter 203.

The tube of the present invention is adapted to provide a continuoushead 215 of urine, led by meniscus 276 from the urinary catheter 203into the down-coming portion 264 of tube 204. A difference in the heightof head 215 above the height of second end 212 provides a negativepressure in the tube.

As will be understood, a negative pressure arises when there is ahydrostatic head as shown, due to a flow of urine in the narrowhydrophobic tube 204 below the vertical level of the urinary catheter203. This negative pressure exerts a sucking action on the bladder 202and prevents the formation of a bolus of urine therein.

Typically, the arrangement comprises tube 204 disposed to provide adown-coming portion 264 proximal to first end 210 and riser portion 266proximal to the second end 212.

The arrangement normally comprises a continuous head of fluid 216 frombladder 202 to the down-corner portion 264 of tube 204.

Arrangement 200 provides a negative height difference between second end212 and bladder 202 to provide said continuously negative fluid pressureof between 5-50 cm water.

Contrary to prior art systems 100, 150, there is no “U shaped”accumulation of urine 164 in the tube and consequentially no air trap166 between loop 268 and the urinary catheter 203. The arrangement ofthe present invention provides a constant head of urine 164 in tube 204,which prevents air from entering bladder 202.

Additionally, the negative pressure in arrangement 200 of the presentinvention prevents the creation of a bolus of urine (not shown) inbladder 202.

As was explained hereinabove, the tube is disposed to provide acontinuously negative fluid pressure of between 5-50 cm water; in somecases between 10-40 cm water; and in other cases, a negative fluidpressure of between 25-40 cm water or the equivalent thereof using adifferent pressure scale as set forth above.

It should be understood that the bladder typically excretes urine,though in some cases, such as during operative procedures the bladdermay release a fluid comprising at least one of urine and blood.

In some cases, catheterized patient 208 may suffer from a UTI prior tobeing connected to the arrangement of the present invention.

Urine collection apparatus 214 may be a bag or other means known in theart.

The arrangement may be constructed and operative to continuously removeurine and/or other liquids 164 from bladder 202 so as to substantiallycontinuously prevent the accumulation of a bolus in the bladder.

According to some embodiments, arrangement 200 is constructed andoperative to provide a continuously negative pressure in bladder 202.Normally, the negative pressure is less than 50 cm equivalent of watertherein or the equivalent thereof.

In preferred embodiments, first end 210 is connected via anon-releasable permanent connector (not shown) to catheter 203. Thecatheter 203, and tube 204 may be integrally formed and adapted for useover a period of time of up to one month, or in some cases, a fortnight.

FIG. 3 shows a catheterization kit 300 comprising a hydrophiliccatheterization tube 302 having a diameter of less than 6 mm andprovided at a first end 304 with means 306 for permanent non-releasableattachment to a catheter 308 and at a second end 310 for releasableattachment 312 to a urine collection bag 314 and a segment of a catheter308.

Catheterization tube 302 is further provided with clamping means 318 tofacilitate the removal and replacement of bag 314 without disturbingnegative pressure within the tube 302 and thereby preventing thepossibility of infection from the tube to the bladder (not shown) and toprevent urine leakage.

As will be realized the catheter unit or at least a part of the catheterunit and or the tube may be made from silicone or from a thermoplasticelastomeric material, other thermoplastic materials, curable elastomericmaterials, polyamide resins or elastomers or any mixture thereof, i.e.the group may comprise materials like, PVC, PU, PE, EVA, latex, and/orKraton™.

In addition in preferred embodiments of the present invention said tubeis provided with internal ridges so as to prevent the blockage thereofin the event of an inadvertent kinking of the tube or pressure thereon.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrative examples and thatthe present invention may be embodied in other specific forms withoutdeparting from the essential attributes thereof, and it is thereforedesired that the present embodiments and examples be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims, rather than to the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

The invention claimed is:
 1. A catheter tube comprising: two ends,adapted for connecting to a catheter at a first end and to a urinecollection bag at a second end, said catheter tube having an innerdiameter of less than six millimeters and having an inner surface whichis hydrophobic and polished, wherein said catheter tube is arranged andconfigured to continuously provide negative pressure in said tube inorder to convey a column of fluid held by a meniscus of said column offluid within said catheter to said collection bag and prevent theformation of an air trap within said catheter tube and prevent aformation of a bolus of urine within a bladder of a patient; and, aclamp disposed on the catheter tube between the first end and the secondend and configured to maintain the negative pressure within saidcatheter tube when said catheter tube is disconnected from the urinecollection bag.
 2. The catheter tube of claim 1, wherein said cathetertube is disposed to provide a continuous negative fluid pressurerepresenting less than 50-centimeter water.
 3. The catheter tube ofclaim 1, wherein said catheter tube is disposed to provide a continuousnegative fluid pressure representing between 10-centimeter to40-centimeter water.
 4. The catheter tube of claim 1, wherein saidcatheter tube is disposed to provide a continuous negative fluidpressure representing between 25-centimeter to 40-centimeter water. 5.The catheter tube of claim 1, wherein said clamp is disposed proximatesaid second end of said catheter tube.
 6. The catheter tube of claim 1,wherein said tube includes a hydrophobic material including at least oneof: a thermoplastic elastomeric material, a thermoplastic material, acurable elastomeric material, a polyamide resin, and an elastomer. 7.The catheter tube of claim 6, wherein said hydrophobic material isselected from at least one of: polypropylene (PP), polyvinyl chloride(PVC), polyurethane (PU), polyethylene (PE), EVA, latex, and Kraton™. 8.The catheter tube of claim 1, wherein said catheter tube comprises anascending portion having a first vertical height and a descendingportion having a second vertical height, wherein a difference betweensaid first vertical height and said second vertical height induces thenegative pressure.
 9. A catheter tube comprising: two ends, adapted forconnecting to a catheter at a first end and to a urine collection bag ata second end, said catheter tube having an inner diameter an innerdiameter of from four millimeters to six millimeters and having an innersurface which is hydrophobic and polished, wherein said catheter tube isarranged and configured to continuously provide negative pressure insaid tube in order to convey a column of fluid held by a meniscus ofsaid column of fluid within said catheter to said collection bag andprevent the formation of an air trap within said catheter tube andprevent a formation of a bolus of urine within a bladder of a patient;and, a clamp disposed on the catheter tube between the first end and thesecond end and configured to maintain the negative pressure within saidcatheter tube when said catheter tube is disconnected from the urinecollection bag.
 10. The catheter tube of claim 9, wherein said cathetertube is disposed to provide a continuous negative fluid pressurerepresenting less than 50-centimeter water.
 11. The catheter tube ofclaim 9, wherein said catheter tube is disposed to provide a continuousnegative fluid pressure representing between 10-centimeter to40-centimeter water.
 12. The catheter tube of claim 9, wherein saidcatheter tube is disposed to provide a continuous negative fluidpressure representing between 25-centimeter to 40-centimeter water. 13.The catheter tube of claim 9, wherein said clamp is disposed proximatesaid second end of said catheter tube.
 14. The catheter tube of claim 9,wherein said tube includes a hydrophobic material including at least oneof: a thermoplastic elastomeric material, a thermoplastic material, acurable elastomeric material, a polyamide resin, and an elastomer. 15.The catheter tube of claim 14, wherein said hydrophobic material isselected from at least one of: polypropylene (PP), polyvinyl chloride(PVC), polyurethane (PU), polyethylene (PE), EVA, latex, and Kraton™.16. The catheter tube of claim 9, wherein said catheter tube comprisesan ascending portion having a first vertical height and a descendingportion having a second vertical height, wherein a difference betweensaid first vertical height and said second vertical height induces thenegative pressure.